1. Field of the Invention
This invention relates generally to mechanisms for countering the steering torque of a boat.
2. Prior Art
A typical prior art outboard motor 10 for a boat is shown in FIG. 1. Motor 10 is pivoted about a vertical axle 11 on a motor mount 12 attached to the stern of a boat (not shown). A control shaft 13 is movably positioned through a sleeve 14 extending transversely through motor mount 12. A follower shaft 15 is positioned through another sleeve 16 in parallel with control shaft 13. A connecting bar 17 is connected between a first end 18 of control shaft 13 and a first end 19 of follower shaft 15, so that when control shaft 13 is moved, follower shaft 15 is moved simultaneously. A link arm 20 is hinged between motor 10 and connecting bar 17. Motor 10 is steered to turn right by moving control shaft 13 toward the right of the figure, and steered to turn left by moving control shaft 13 toward the left of the figure.
The torque generated by motor 10 tends to pivot motor 10 counterclockwise about axle 11 and steer the boat right, as shown in FIG. 2. The driver of the boat must constantly resist the right-turning tendency by counter steering with the steering wheel. The constant application of counter steer is tiring. Further, if the driver releases the steering wheel, or if there is a failure in the steering linkage, the torque from motor 10 will automatically snap the boat into a sharp, uncontrolled right turn.
A steering mechanism disclosed in U.S. Pat. No. 4,263,994 to Hayes prevents outboard motor torque from feeding back to a steering wheel. It is a replacement for a preexisting steering mechanism, not an add-on. It requires numerous arms and links, so that it is complicated to make and install.
Accordingly, objects of the present boat steering torque compensator are:
to precisely counteract torque from an outboard motor;
to eliminate the need for a driver to apply counter steer on the steering wheel;
to eliminate a boat""s natural tendency to turn even when the driver releases the steering wheel, or during steering linkage failure; and
to be easily retrofitted to a boat without modifying or dissembling an existing steering linkage.
Further objects of the present invention will become apparent from a consideration of the drawings and ensuing description.
The present boat steering torque compensator is for being attached to a boat with a pivotable outboard motor, and a linearly movable control shaft with a first end connected to the outboard motor and a second end connected to a steering wheel. The compensator is comprised of a tube for being attached to the boat in a fixed position parallel to the control shaft. A compression spring positioned in the tube has a fixed first end adjacent the first end of the control shaft, and a movable second end. An elongated shaft positioned in the tube and through the spring has a first end connected to the first end of the control shaft by an adapter arm, and a second end positioned adjacent the movable second end of the spring. An engaging member on the second end of the elongated shaft engages the movable second end of the spring to compress the spring when the control shaft and elongated shaft are moved in the direction of the first end of the tube. As a result, the tendency of the motor to pivot under the influence of motor torque is opposed by the spring. The engaging member on the elongated shaft disengages and moves away from the movable second end of the spring when the control shaft and elongated shaft are moved in the direction of the second end of the tube, so that the control shaft is free to move independently of the spring.